If a side marker does not illuminate with headlamps or parking lights, it should be:

In the context of automobile safety inspections, side markers play a crucial role in enhancing visibility and indicating the presence of a vehicle to others, especially during low-light conditions. The requirement for side markers to illuminate when the headlamps or parking lights are activated is essential for safety compliance.

When a side marker does not illuminate as it is supposed to with these lights, it indicates a failure to meet the safety standards set forth for vehicles. Such a malfunction could jeopardize the visibility of the vehicle, particularly for those approaching from the side. It becomes a significant safety concern that necessitates corrective action.

As a result, the appropriate response is to categorize the vehicle as 'failed' in this inspection aspect. This ensures that the necessary repairs are made to restore proper functionality before the vehicle can be deemed safe for operation on the road. By failing the vehicle for this issue, inspectors uphold the standards designed to protect all road users, ensuring vehicles are correctly equipped to signal their position at all times.